Celia V. Riga

Treatment of Complex Aneurysmal Disease with Fenestrated and Branched Stent Grafts

OBJECTIVES To describe our experience of treating juxtarenal (JRAAAs <4mm neck) and thoracoabdominal aortic aneurysms (TAAAs) using fenestrated and branched stent graft technology. DESIGN Prospective single centre experience. METHODS Since 2005, 29 fenestrated/branched procedures have been performed. 15 patients are studied with JRAAAs (n=7; median neck length 0mm (IQR 0-3.8)) or TAAAs (type I (n=2), III (n=2), IV (n=4)). ASA grade III in 12/15. Maximum diameter of aneurysm 64 mm (56-74 mm). Aneurysms were excluded using covered stents or branches from the main body to patent visceral vessels (40 target vessels total). Pre-operative and follow-up CT scans (1, 3, and 12 months) were analysed by a single Vascular Interventional Radiologist. RESULTS Technical success for cannulation and stenting of target vessels was 98%. In-hospital mortality was 0%. One patient underwent conversion to open repair. Five had major complications including one paraplegia (type III TAAA) with subsequent recovery. Median length of stay was 9 days (IQR 7-18.75). At a median follow-up of 12 months (9-14), CT confirmed 36/37 (97%) target vessels remain patent. Sac size increased >5 mm in one patient only. There were no type I endoleaks, three type II endoleaks (one embolised, two under surveillance) and three type III endoleaks (two successfully treated percutaneously, one aneurysm ruptured 18 months after endografting and died). CONCLUSION In selected patients, fenestrated and branched stents appear to be a safe and effective alternative to surgery for juxtarenal and thoracoabdominal aneurysms. The complication and mortality rates are low. The long-term durability of this procedure, however, needs to be proven.

Evaluation of robotic endovascular catheters for arch vessel cannulation.

OBJECTIVE Conventional catheter instability and embolization risk limits the adoption of endovascular therapy in patients with challenging arch anatomy. This study investigated whether arch vessel cannulation can be enhanced by a remotely steerable robotic catheter system. METHODS Seventeen clinicians with varying endovascular experience cannulated all arch vessels within two computed tomography-reconstructed pulsatile flow phantoms (bovine type I and type III aortic arches), under fluoroscopic guidance, using conventional and robotic techniques. Quantitative (catheterization times, catheter tip movements, vessel wall hits, catheter deflection) and qualitative metrics (Imperial College Complex Endovascular Cannulation Scoring Tool [IC3ST]) performance scores were compared. RESULTS Robotic catheterization techniques resulted in a significant reduction in median carotid artery cannulation times and the median number of catheter tip movements for all vessels. Vessel wall contact with the aortic arch wall was reduced to a median of zero with robotic catheters. During stiff guidewire exchanges, robotic catheters maintained stability with zero deflection, independent of the distance the catheter was introduced into the carotid vessels. Overall IC3ST performance scores (interquartile range) were significantly improved using the robotic system: Type I arch score was 26/35 (20-30.8) vs 33/35 (31-34; P = .001), and type III arch score was 20.5/35 (16.5-28.5) vs 26.5/35 (23.5-28.8; P = .001). Low- and medium-volume interventionalists demonstrated an improvement in performance with robotic cannulation techniques. The high-volume intervention group did not show statistically significant improvement, but cannulation times, movements, and vessel wall hits were significantly reduced. CONCLUSION Robotic technology has the potential to reduce the time, risk of embolization and catheter dislodgement, radiation exposure, and the manual skill required for carotid and arch vessel cannulation, while improving overall performance scores.

Analysis of Flow Patterns in a Patient-Specific Aortic Dissection Model

Aortic dissection is the most common acute catastrophic event affecting the thoracic aorta. The majority of patients presenting with an uncomplicated type B dissection are treated medically, but 25% of these patients develop subsequent aneurysmal dilatation of the thoracic aorta. This study aimed at gaining more detailed knowledge of the flow phenomena associated with this condition. Morphological features and flow patterns in a dissected aortic segment of a presurgery type B dissection patient were analyzed based on computed tomography images acquired from the patient. Computational simulations of blood flow in the patient-specific model were performed by employing a correlation-based transitional version of Menters hybrid k-epsilon/k-omega shear stress transport turbulence model implemented in ANSYS CFX 11. Our results show that the dissected aorta is dominated by locally highly disturbed, and possibly turbulent, flow with strong recirculation. A significant proportion (about 80%) of the aortic flow enters the false lumen, which may further increase the dilatation of the aorta. High values of wall shear stress have been found around the tear on the true lumen wall, perhaps increasing the likelihood of expanding the tear. Turbulence intensity in the tear region reaches a maximum of 70% at midsystolic deceleration phase. Incorporating the non-Newtonian behavior of blood into the same transitional flow model has yielded a slightly lower peak wall shear stress and higher maximum turbulence intensity without causing discernible changes to the distribution patterns. Comparisons between the laminar and turbulent flow simulations show a qualitatively similar distribution of wall shear stress but a significantly higher magnitude with the transitional turbulence model.

Prevention of Paraplegia during Thoracoabdominal Aortic Aneurysm Repair

Paraplegia affects up to 22% of patients undergoing thoarcoabdominal aneurysm surgery, producing long-term morbidity and a significant burden to healthcare. This article discusses the mechanisms that may lead to paraplegia during open and endovascular repair from an anatomical and physiological perspective. There are many adjuncts that must be considered to reduce the risk of spinal cord injury, such as revascularisation of intercostal arteries, maintenance of high mean blood pressure, spinal cord drainage and cooling. These adjuncts are discussed, highlighting the evidence available for each method and the practical ways in which they may be used.

The role of robotic endovascular catheters in fenestrated stent grafting

OBJECTIVE Fenestrated stent grafting has allowed the treatment of complex thoraco-abdominal aneurysm disease via a totally endovascular approach, but the procedure can be technically challenging and time consuming. We investigated whether this procedure may be enhanced by remotely steerable robotic endovascular catheters. METHODS A four-vessel fenestrated stent graft partially deployed within a computed tomography (CT)-reconstructed pulsatile thoraco-abdominal aneurysm silicon model was used. Fifteen operators were recruited to participate in the study and divided into three groups, based on their endovascular experience: group A (n = 4, 100-200 endovascular procedures, group B (n = 5, 200-300), and group C (n = 6, >300). All operators were asked to cannulate the renal and visceral vessels under fluoroscopic guidance, using conventional and robotic techniques. Quantitative (catheterization times and wire/catheter tip movements) and qualitative metrics (procedure-specific-rating scale [IC3ST]), which grades operators on catheter use, instrumentation, successful cannulation/catheterization, and overall performance were compared. RESULTS Median procedure time for cannulation of all four vessels was reduced using the robotic system (2.87 min, interquartile range [IQR; 2.20-3.90] versus 17.24 min [11.90-19.80]; P < .001) for each individual operator, regardless of the level of endovascular experience. The total number of wire/catheter movements taken to complete the task was also significantly reduced (38, IQR [29-57] versus 454 [283-687]; P < .001). There were significant differences in time and movement for cannulation of each individual vessel in the phantom. Robotic catheter operator radiation exposure was negligible as the robotic workstation is remote and away from the radiation source. Overall performance scores significantly improved using the robotic system, despite minimal operator exposure to this technology (IC3ST score 29/35, IQR [22.8-30.7] versus 19/35 [13-24.3]; P = .002). Each group of operators demonstrated an improvement in performance with robotic cannulation. For group A, median IC3ST score was 28/35, IQR (22-33) versus 15/35 (11-20); P = .04; for group B, 30/35 (27-31) versus 19/35 (18-24); P = .07; and for group C, 28.8/35 (28.5-29) versus 22/35 (16-24); P = .06. For groups B and C, these differences did not reach statistical significance. CONCLUSION Robotic catheterization of target vessels during this procedure is feasible and minimizes radiation exposure for the operator. Steerable robotic catheters with intuitive control may overcome some of the limitations of standard catheter technology, enhance target vessel cannulation, reduce instrumentation, and improve overall performance scores.

Contemporary management of splanchnic and renal artery aneurysms: results of endovascular compared with open surgery from two European vascular centers.

INTRODUCTION Splanchnic and renal artery aneurysms (SRAAs) are uncommon but potentially life-threatening in case of rupture. Whether these aneurysms are best treated by open repair or endovascular intervention is unknown. The aim of this retrospective study is to report the results of open and endovascular repairs in two European institutions over a fifteen-year period. We have reviewed the available literature published over the 10 last years. METHODS All patients with SRAAs diagnosed from 1995 to 2010 in St Marys Hospital (London, UK) and Henri Mondor Hospital (Créteil, France) were reviewed. Preoperative clinical and anatomical data, operative management and outcomes were recorded from the charts and analyzed. RESULTS 40 patients with 51 SRAAs were identified. There were 21 males and 19 females with a mean age of 57 ± 14.9 years. The aneurysms locations were: 14 (27%) renal, 11 (22%) splenic, 7 (14%) celiac trunk, 7 (14%) superior mesenteric artery, 4 (8%) hepatic, 4 (8%) pancreaticoduodenal arcades, 3 (6%) left gastric and 1 (2%) gastroduodenal. 4 patients presented with a ruptured SRAA. 17 SRAAs in 16 patients were treated by open repair, 15 in 15 patients were treated endoluminally and 17 (mean diameter: 18 mm, range: 8-75 mm) were managed conservatively. One patient with metastatic pulmonary cancer with two mycotic aneurysms of the superior mesenteric artery (75 mm) and celiac trunk (15 mm) was palliated. After endovascular treatment, the immediate technical success rate was 100%. There was no significant difference between open repair and endovascular patients in terms of 30-day post-operative mortality rate and peri-operative complications. No in-hospital death occurred in patients treated electively. Postoperatively, four patients (1 ruptured and 3 elective) suffered non-lethal mild to severe complication in the open repair group, as compared with one in the endovascular group (p = .34). The mean length of stay was significantly higher after open repair as compared with endovascular repair (17 days, range: 8-56 days vs. 4 days, range: 2-6; p < .001). The mean follow-up time was 17.8 months (range: 0-143 months) after open repair, 15.8 months (range: 0-121 months) after endovascular treatment, and 24.8 (range: 3-64 months) for patient being managed conservatively. No late death related to the VAA occurred. In each group, 2 successful reoperations were deemed necessary. In the endovascular group, two patients presented a reperfusion of the aneurysmal sac at 6 and 24 months respectively. CONCLUSION No significant difference in term of 30-day mortality and post-operative complication rates could be identified between open repair and endovascular treatment in the present series. Endovascular treatment is a safe alternative to open repair but patients are exposed to the risk of aneurysmal reperfusion. This mandates careful long-term imaging follow up in patients treated endoluminally.

Robot-assisted Fenestrated Endovascular Aneurysm Repair (FEVAR) Using the Magellan System

A 67-year-old man underwent robot-assisted three-vessel fenestrated endovascular aneurysm repair (FEVAR) for a 7.3-cm juxtarenal aneurysm. The 6-F robotic catheter was manipulated from a remote workstation, away from the radiation source. Robotic cannulation of the left renal artery was achieved within 3 minutes. System setup time was 5 minutes. There were no postoperative complications. Computed tomography angiography performed at discharge and at 4-month follow-up confirmed target vessel patency with no evidence of an endoleak. Selective cannulation of target vessels during FEVAR using this novel technology is feasible. Endovascular robotics may have a role in simplifying complex endovascular tasks and potentially reducing radiation exposure to the operator.

Initial Clinical Application of a Robotically Steerable Catheter System in Endovascular Aneurysm Repair

Purpose: To report the initial clinical use of a robotically steerable catheter during endovascular aneurysm repair (EVAR) in order to assess this novel and innovative approach in a clinical setting. Technique: Following a series of in-vitro studies and procedure rehearsals using a pulsatile silicon aneurysm model, a 78-year-old man underwent robot-assisted EVAR of a 5.9-cm infrarenal abdominal aortic aneurysm. During the standard procedure, a 14-F remotely steerable robotic catheter was used to successfully navigate through the aneurysm sac, cannulate the contralateral limb of a bifurcated stent-graft under fluoroscopic guidance, and place stiff wires using fine and controlled movements. The procedure was completed successfully. There were no postoperative complications, and computed tomographic angiography prior to discharge and at 3 months confirmed that the stent-graft remained in good position, with no evidence of an endoleak. Conclusion: EVAR using robotically-steerable catheters is feasible. This technology may simplify more complex procedures by increasing the accuracy of vessel cannulation and perhaps reduce procedure times and radiation exposure to the patient and operator.

Segmental arterial mediolysis: a systematic review of 85 cases.

BACKGROUND Segmental arterial mediolysis (SAM) is a nonatherosclerotic, noninflammatory arteriopathy of unknown etiology with life-threatening manifestations. With advances in endovascular techniques, SAM is increasingly being managed without the need for major surgery. METHODS A systematic review of the literature published on SAM between 1976 and 2012 was performed, focusing on arterial involvement, diagnostic imaging modalities, mortality and morbidity rates, and in particular treatment outcomes with open versus endovascular intervention. RESULTS Sixty-two studies reporting on 85 cases of SAM were reviewed. Sixty-nine percent of cases were diagnosed histologically (24% on autopsy). Angiography was the most common form of diagnostic imaging modality (56% of cases). Arterial involvement was largely abdominal or cranial, with splenic arterial involvement being the most prevalent (29% of cases). There was a total SAM-related mortality of 26%. Endovascular intervention, most commonly in the form of coil embolization of aneurysmal vessel(s), was successful in 88% of cases where attempted, with no reported mortality. There was a mortality rate of 9% where open surgery was attempted. CONCLUSIONS Catheter-based endovascular techniques can be a successful, minimally invasive treatment option in the management of this potentially life-threatening condition, and may also provide a temporary bailout measure in the acute phase before definitive surgical treatment at a later stage.

Surgical technology and operating-room safety failures: a systematic review of quantitative studies

Background Surgical technology has led to significant improvements in patient outcomes. However, failures in equipment and technology are implicated in surgical errors and adverse events. We aim to determine the proportion and characteristics of equipment-related error in the operating room (OR) to further improve quality of care. Methods A systematic review of the published literature yielded 19 362 search results relating to errors and adverse events occurring in the OR, from which 124 quantitative error studies were selected for full-text review and 28 were finally selected. Results Median total errors per procedure in independently-observed prospective studies were 15.5, interquartile range (IQR) 2.0–17.8. Failures of equipment/technology accounted for a median 23.5% (IQR 15.0%–34.1%) of total error. The median number of equipment problems per procedure was 0.9 (IQR 0.3–3.6). From eight studies, subdivision of equipment failures was possible into: equipment availability (37.3%), configuration and settings (43.4%) and direct malfunctioning (33.5%). Observed error rates varied widely with study design and with type of operation: those with a greater burden of technology/equipment tended to show higher equipment-related error rates. Checklists (or similar interventions) reduced equipment error by mean 48.6% (and 60.7% in three studies using specific equipment checklists). Conclusions Equipment-related failures form a substantial proportion of all error occurring in the OR. Those procedures that rely more heavily on technology may bear a higher proportion of equipment-related error. There is clear benefit in the use of preoperative checklist-based systems. We propose the adoption of an equipment check, which may be incorporated into the current WHO checklist.